IPhone question. Can I buy a phone on Amazon, if I have a MetroPCS account for my present iPhone?

I am thinking of buy one the iPhone I want on Amazon. It is for T-Mobile and is renewed. So, my question is, can I buy a phone from this company even though I pay my present phone through Metro (which is part of T-Mobile now)? I can call them and find out, though I would ask here first if someone knows. By the way, my iPhone was also bought through Metro. However their present deals are too expensive, and I'm finding some great deals on Amazon.

IPhone question. Can I buy a phone on Amazon, if I have a MetroPCS account for my present iPhone?
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